1. Technical Field
The present invention relates to electro-optical devices and electronic apparatuses.
2. Related Art
Electro-optical devices, such as liquid crystal devices that display images by utilizing liquid crystal, are known. Such a liquid crystal device includes a liquid crystal panel and backlight, which serves as an illumination device. The liquid crystal panel includes a display area having a plurality of pixels, a scanning line drive circuit, and a data line drive circuit. The scanning line drive circuit and the data line drive circuit are disposed around the display area to drive the pixels. The plurality of pixels include three types of pixels, i.e., pixels having a red (R) color filter, pixels having a green (G) color filter, and pixels having a blue (B) color filter.
The liquid crystal panel includes an element substrate on which thin-film transistors (TFTs), which serve as switching elements, are disposed in association with the pixels, a counter substrate disposed opposedly facing the element substrate, and liquid crystal, which serves as an electro-optical material, held between the element substrate and the counter substrate.
The element substrate includes a plurality of scanning lines disposed at regular intervals, a plurality of data lines disposed at regular intervals and crossing substantially at right angles with the corresponding scanning lines, and TFTs and pixel electrodes disposed at the intersections between the corresponding scanning lines and the corresponding data lines. The counter substrate includes counter electrodes disposed opposedly facing the pixel electrodes.
Each pixel includes a storage capacitor in addition to the above-described TFT, pixel electrode, and counter electrode. The scanning lines are connected to the gates of the corresponding TFTS, the data lines are connected to the sources of the corresponding TFTS, and the pixel electrodes and the storage capacitors are connected to the drains of the corresponding TFTS.
The liquid crystal device configured as described above operates as follows. The scanning line drive circuit line-sequentially supplies a selection voltage to the scanning lines one by one so that all the pixels of a certain scanning line are selected. In synchronization with the selection of the pixels, the data line drive circuit supplies image signals to the data lines. With this operation, an image signal is supplied from the data line via the switching element to the pixel selected by the scanning line drive circuit and the data line drive circuit so that image data can be written into the pixel electrode.
When the image data is written into the pixel electrode, a drive voltage is applied to the liquid crystal due to the potential difference of the voltage applied to the pixel electrode and the counter electrode. By varying the voltage level of the image signal, the orientation and order of the liquid crystal are changed so that grayscale display is implemented by light modulation of the individual pixels. Because of the provision of the storage capacitors, the drive voltage applied to the liquid crystal is held over a period longer than the period for which the image data is written into the pixel electrodes by three orders of magnitude.
There is an increasing demand for saving power of electro-optical devices. To address such a demand, an electro-optical device in which address lines that specify areas to be selected by scanning lines are disposed substantially parallel with data lines has been proposed (see Japanese Patent No. 3428593).
In the electro-optical device disclosed in the above publication, areas to be selected by the scanning lines are specified by the address lines. Accordingly, an image signal can be supplied only to the pixels in a selected area, thereby implementing power saving. For example, when the movement of a cursor in a still image is displayed, an area including pixels representing the moving cursor is specified by the corresponding address line. Then, for the pixels representing the moving cursor, i.e., the pixels forming an area of a display image to be changed, an image signal is supplied to each frame. Conversely, for the pixels representing the still image, i.e., the pixels forming an area of the display image to remain unchanged, an image signal is supplied to every other frame. In this case, power can be saved more efficiently than the case where an image signal is supplied to all pixels of each frame.
In the above-described electro-optical device, three types of pixels periodically disposed are grouped into one block, and an address line is provided at the boundary of adjacent blocks. Accordingly, the gap between adjacent pixels across an address line is larger than the gap between adjacent pixels without an address line.
The address lines are provided between two specific types of pixels of the three types of pixels. For example, if one block is composed of three types of pixels, i.e., R, G, and B pixels, disposed in that order, an address line is provided between an R pixel and a B pixel.
Thus, since the address lines are provided between the two specific types of pixels among the three types of pixels, the gap between the two specific types of pixels is larger than the gap between other adjacent pixels. Accordingly, pixels forming a display image concentrate on the two specific types of pixels, and as a result, special stripe or spot-like patterns appear, thereby decreasing the image quality.